10.2 Protecting Primary Storage Pools with Active-data Storage Pools

Active-data pools are storage pools that contain only active versions of client backup data. When the new backup data continue to be stored in active-data pools, older versions are deactivated and removed during reclamation processing.

You can issue the COPY ACTIVEDATA command, either manually or in an administrative schedule or maintenance script, to copy active versions of client backup files from primary storage pools to active-data pools. (The BACKUP STGPOOL command is not supported for active-data pools.) Alternatively, you can use the simultaneous-write function to automatically write active backup data to active-data pools at the same time the backup data is written to a primary storage pool.

Active Data Storage pools Overview

Active-data pools can use any type of sequential-access storage (for example, a tape device class or FILE device class). However, the precise benefits of an active-data pool depend on the specific device type associated with the pool. For example, active-data pools associated with a FILE device class are ideal for fast client restores because FILE volumes do not have to be physically mounted and because the server does not have to position past inactive files that do not have to be restored. |In addition, client sessions restoring from FILE volumes in an active-data |pool can access the volumes concurrently, which also improves restore performance. Features of active-data pools on sequential-access disk (FILE)

Optimized access to active versions for faster restore operations

Reduced size of disk pool if only stores active versions

Reduced data movement in preparation of the restore of active data

Active-data pools that use removable media, such as tape or optical, offer similar benefits. Although tapes need to be mounted, the server does not have to position past inactive files. However, the primary benefit of using removable media in active-data pools is the reduction of the number of volumes used for onsite and offsite storage.

If you vault data electronically to a remote location, an active-data pool associated with a SERVER device class lets you save bandwidth by copying and restoring only active data. Features of active-data pools on tape

Policy Domains bind the nodes that can store data into an active-data pool. Before Tivoli Storage Manager writes data to an active-data pool, it verifies that the node that owns the data is assigned to a domain. That domain must have the active-data pool defined in the ACTIVEDESTINATION parameter.

You can decide whether to copy and update an existing domain or establish a new policy in which the domain authorizes nodes to store data in an active-data pool. To use an existing domain, use the UPDATE DOMAIN command and specify the list of active-data pools in the ACTIVEDESTINATION parameter.

update domain domainname activedatapool=activedatastgpoolname

Manually Copying Active data

You can also use Copy Activedata command to copy active versions of backup data from a primary storage pool to an active-data pool. If a file already exists in the active-data pool, the file is not copied unless the copy of the file in the active-data pool is marked damaged. However, a new copy is not created if the file in the primary storage pool is also marked damaged. In a random-access storage pool, neither cached copies of migrated files nor damaged primary files are copied.

If migration for a storage pool starts while active data is being copied, some files might be migrated before they are copied. For this reason, you should copy active data from storage pools that are higher in the migration hierarchy before copying active data from storage pools that are lower. Be sure a copy process is complete before beginning another.

Regardless of whether you use the COPY ACTIVEDATA command or simultaneous write, the Tivoli Storage Manager will only write data to an active-data pool if the data belongs to a node that is a member of a policy domain that specifies the active-data pool as the destination for active data.